The invention lies in the field of electrical engineering. More specifically, the invention relates to a control apparatus for carrying out switching operations in a switchgear assembly, in particular in a high-voltage or medium-voltage installation.
Switching operations are repeatedly necessary in switchgear assemblies in a power supply network for selectively supplying or disconnecting electrical assemblies. Switching operations must thereby be carried out to a different extent, owing to the large number of functions integrated in modern switchgear assemblies. One such switching operation is, for example, the connection or disconnection of a circuit-breaker, with corresponding connection or disconnection of voltage to or from an electrical equipment. Another switching operation is the opening or closing of a switch-disconnector, with corresponding production or closing of an isolating gap required for safety reasons. Furthermore, a switching operation may be the connection or disconnection of a grounding switch, with corresponding grounding and short-circuiting of a power supply section, for example for process-technical reasons.
It is absolutely necessary during the operation of such a switchgear assembly, that the switching operations be carried out in a specific sequence. The sequence of switching operations is referred to in the art as a switching program. The extent of such a switching program may differ and may comprise, for example, only the switching of the circuit-breaker, of the switch-disconnector, of the grounding switch, or a combination of these switching operations. The isolating and grounding function are thereby subject to particular conditions, on the basis of which isolation and non-energized grounding may be carried out only without power. Various interlock systems between the functions are used to guarantee that these conditions are satisfied at all times.
In order to allow medium-voltage switchgear assemblies to be operated, the German Standard (DIN VDE, IEC) requires that operators be trained to become authorized switchgear operators, who may therefore carry out these switching operations. The respective operating states are monitored by a mechanic or a secondary technician, who identifies the switch positions and generates an appropriate message. In this case, the switching operations may be carried out manually, locally, or by remote control, the grounding normally being carried out locally. Control errors when carrying out switching operations manually can result in severe injuries to personnel and damage to equipment.
Japanese Patent Abstract JP 06 195 101 (JP Applic. 04343013) discloses a control apparatus for controlling a device in a system having a magnetic memory card. The memory card is used to store control information and system control information, by means of which, in general, an enable signal and a control signal can be produced for the device.
U.S. Pat. No. 5,233,511 to Bilas et al. discloses a system for remote control of interrupters for interrupting an electrical power supply temporally during peak-load periods and for programmable lighting monitoring for industrial sites, that is to say in a low-voltage network. The system has a key card mechanism with an automatic interpreter, by means of which a coded message incorporated on a key card can be interpreted. If required, this allows an operator to have access to monitor the interrupter. The key card mechanism is used to prevent unauthorized access to system programming functions. The coded message is stored on the coded key card in the form of a hole pattern which is detected optically in a card reader.
The Siemens company prospectus xe2x80x9cSchaltfehlerschutz 8TKxe2x80x9d [Switching Fault Protection 8TK], 1985, Order No. A-19100-E135-B283 discloses a so-called switching fault protective device for high-voltage and medium-voltage systems, which is used, inter alia, for manual control of switchgear. There, the reliability of switching operations carried out manually is monitored in accordance with interlock conditions which can be specified in advance. In principle, the interlock conditions may be rendered ineffective via various control buttons. In order to authorize the operation of the switching fault protective device, appropriate key-operated switches may be provided, which enable the operation of the device on the basis of switching authorization.
It is accordingly an object of the invention to provide a control apparatus for carrying out switching operations with a switchgear assembly, which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which affords a particularly high level of reliability and automation.
With the foregoing and other objects in view there is provided, in accordance with the invention, in combination with a high-voltage or medium-voltage switchgear assembly having a plurality of controlled devices such as a power breaker, a switch disconnector, and/or a grounding switch disposed in a switch panel of the assembly, a control apparatus for controlling the controlled devices, comprising:
an electronic memory card adapted to store operating authorization for the switchgear assembly and to store system control information defining a switching program with a number of control data items representing a sequence of switching operations;
the control data items automatically producing control signals for initiating at least one switching operation within the switch panel for at least one of the controlled devices.
The use of such a memory card or switching card allows the execution of the switching programs to be initiated, monitored and appropriately documented virtually without any faults, and thus particularly safely, automatically. At the same time, the switching card can carry out the function of authorization control. Switching operations independently of authorization control may therefore be carried out only by the holder of the memory card. This results in standardization of the design of the interlock technology.
In accordance with an added feature of the invention, the memory card includes a memory from which the control data items can be read. The control data items represent a sequence of switching operations. In order to read out the control data for the switch or each switch in the switchgear assembly, the memory card can expediently be inserted in a card reader which is provided in a control interface of the switchgear assembly, and a plurality of control interfaces with associated card readers may also be provided. The switching operations are then executed by sending the stored control data via control lines which lead to the switches in the switchgear assembly and are connected to the card reader. The control data then initiate, for example, auxiliary voltages for the respective switching process. At the same time, each switching operation carried out may be indicated on the control panel by visualization of the respective switch position.
In accordance with an additional feature of the invention, there is provided an output device, such as a printer, for recording each switching operation carried out using the memory card.
In accordance with another feature of the invention, the memory card is programmable. To this end, a switching program with a specific sequence of switching operations can be written to the memory card. The stored switching program can be overwritten with a new switching program, by reprogramming. The essential feature in this case is the programming of the respective switching operation to be carried out such as, in particular, the switching of a circuit breaker, of a switch-disconnector and/or of an grounding switch, in a specific sequence. Any required combinations of individual switching operations may be programmed in this case. Further information items, in particular coding of assemblies or system sections allocated to the system, a specific date and/or a specific time, may be programmed in the memory card as additional stored data.
In accordance with a further feature of the invention, the memory card is further adapted to store thereon access authorization to the switchgear assembly. In that case, a door opener code for the switchgear assembly door is stored in the memory card, as additional information. The programming process is carried out by automatically writing to the memory card by means of a computer, and is ended with the switching program required for the respective purpose.
The invention may also be summarized as an improved control apparatus for controlling a system device via a memory card adapted to store control information and system control information, and to cause an enable signal and a control signal to be produced for the device. The improvement comprises the following:
the system is a high-voltage or medium-voltage switchgear assembly having, if necessary, further devices;
the system devices are a plurality of devices such as a power
breaker, a switch disconnector, and/or a grounding switch arranged in a switch panel in the system;
the memory card is an electronic memory card;
the control information stored on the memory card represents operating authorization;
the system control information stored on the memory card forms a switching program with a number of control data items representing a sequence of switching operations; and
control signals for initiating at least one switching operation in the switch panel are automatically produced for at least one of the devices using the control data.
The advantages achieved by the invention are, in particular, that the use of an electronic memory card for variable storage of control data which automatically initiate the switching operation or each switching operation ensures that the control process is simplified with, at the same time, a particularly low time and labor cost and a high level of safety. Incorrect control operations are in consequence virtually precluded. Furthermore, a high level of standardization as well as high speed in the control sequences are achieved even over relatively long distances, with standard and reliable documentation of the switching processes (responsibility) also being possible.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a control apparatus for carrying out switching operations in a switchgear assembly, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.